To scan files uploaded by user for .net framework using file upload control

I am new to using this software..My requirement is to do the scanning of files uploded by a user through the web application in real time.I am working on .net framework.What is the process to start with using it.. I havent got any link which can actually give an idea from the basics as how to use it..I wanted to know from where i can download the .net API and the example code for how to use it in my application.Firstly i wanted to test in using trail version so has to precure it later on.. Plzz help..